1. Field of the Invention
The present invention relates to a switching power source apparatus.
2. Description of Related Art
Conventionally, as power sources for various applications, switching power source apparatuses of PWM [pulse width modulation] drive type are widely used.
The switching power source apparatus of PWM drive type has generally, as circuit elements forming its voltage feedback loop, an error amplifier that generates an error voltage in accordance with a difference between an output voltage or a feedback voltage corresponding to the output voltage and a predetermined reference voltage; a slope voltage generation circuit that generates a slope voltage; and a PWM comparator that compares the error voltage and the slope voltage with each other to decide an off-timing of an output transistor.
In the meantime, as an example of the prior art relevant to the above description, there is JP-A-2011-142795.
However, in the conventional switching power source apparatus, there are problems that a higher switching frequency leads to a severer duty restriction because of an internal delay of the PWM comparator and it becomes unable to decrease the output voltage.